Recently “re-discovered” so-called Magic Sponges™ . They work for cleaning walls, etc., but they turn out to be, well, magical for cleaning extra ink & paint off of engraved tiles (any a myriad of other uses). The only drawback for me was the outrageous prices for the store brands.
Just received a big bag of these for ~$9 from Amazon, and they work a treat for about 1/10th the cost!
…btw, all my Mac keyboards are now spic-n-span™, so to speak. Be sure to use the absolute minimum amount of water (just a few drops, then wring out till only slightly damp) so you don’t kill your electronics… YMMV, don’t try this at home.